The Trials and Fall of Castiel
by reachingforthestardust
Summary: Castiel is falling, again. Sam is without hope. Dean is a demon. So when Castiel gets it into his head that he should attempt the Hell Trials and save Dean, Sam goes along with it, seizing the chance to save his brother, no matter what the cost. And when Cas's true intentions are finally revealed, it's already far too late to go back.
1. The Beginning

It almost could have been the start of a bad joke. A semi-fallen angel and Lucifer's ex-vessel sat together in a secret hideout. Sadly, it wasn't a joke, and it was the harsh reality of Castiel's world, which very recently had imploded. He was sitting beside Sam in the Men of Letters bunker, both of them staring blankly into empty space, a sorry pair soaking in their own misery and suffering.

Castiel was the first to break the silence. "What were the trials to close Hell?" He asked, and Sam didn't even lift his head as he replied.

"Bathe in the blood a hellhound, rescue an innocent soul from Hell and cure a demon," he said flatly, his thoughts focused on what Dean might be doing, what evil and chaos he might be creating. He remembered Dean mentioning that when Cain had received the Mark he'd murdered thousands – Sam shuddered to think of his older brother following in such footsteps.

Castiel was silent for a moment, considering, thoughtful. Then, "I think I have an idea."

"And what would that be, Cas," Sam asked mockingly, his voice eerily reminiscent of Zachariah's. "Can you give me back my brother? Can you fix the world?"

Cas wasn't thrown by Sam's bitterness in the slightest, his mind connecting dots faster than a human, but far slower than an Angel. "Yes," he said slowly, not rising to Sam's provoking tone. "Yes, I think I can."

Sam's head snapped to face Cas, the angel's words sinking through the haze of fear and sorrow at last. "What?"

"If I complete the trials, I can fix everything," Cas murmured distractedly, thoughts still racing.

Sam snorted. "Yeah, but you still won't give me back Dean. He'd just be stuck in Hell, _forever_." His grief-filled mind still wasn't quite up to speed, and Cas shook his head in disagreement, finally looking over at Sam with a piercing gaze.

"Not if I cure him."


	2. To Bathe In Blood

"Cas, are you sure you want to do this?" Sam asked, patting his pocket to check he had his hellhound glasses. The pair were sitting in the Impala outside an apartment building, checking and double-checking they had all necessary equipment to take down a hellhound.

The angel raised his eyes to Sam's. "I'm sure," Cas reassured the hunter. "If I wasn't, we wouldn't be here."

It was a month since the fateful day when Cas had put together the pieces to save Dean and to end Hell's terror on Earth. Sam hadn't hesitated to hop on board Cas's thought train, instantly beginning a search for a ten-year debt coming due. The pair had made a good team, bouncing ideas off of each other, researching silently for hours and eventually coming up with the goods. Neither of the pair, however, raised the topic of the end result of the third trial; they had come to an unspoken agreement that it was not to be discussed.

But for the moment, they had yet to succeed in the first trial, which was why they were currently in Fort Smith, Arkansas. Sam's attention had been caught by the sudden rise to fame of the chef Cameron Walsh nearly ten years earlier, and had done some poking around, discovering that Walsh had been incarcerated in several mental facilities prior to his success, the psychological reports stating that he was 'dangerously obsessed with the occult'.

Some more digging had revealed that the tenth anniversary of Walsh's rise to fame would take place in a month. Sam had informed Cas of his discovery, and the duo agreed – it definitely smelt like a demon deal – prior to a decade ago, Walsh had had little to no talent with the culinary arts, and according to yet another psychological report he'd actually set fire to a kitchen whilst trying to poach eggs. So here they were, a month later, about to try the first task.

Castiel slipped his own glasses onto his nose, trying very hard to ignore the fact that the last person to wear them had been Dean. He couldn't afford distractions right now, and by his father, was the subject of Dean distracting. Cas shoved all thoughts of the once-Righteous Man to the back of his mind, focusing on the trial, or rather, the task, at hand. There would be time to wallow after, he reminded himself. For now, focus.

Cas shifted slightly in the passenger seat, clutching the demon knife tightly. He cleared his throat, and looked away from Sam, out the window. "Let's go."

"Cas, wait," Sam said, reaching over and putting his large hand on the angel's shoulder. "You do realise that this isn't going to be a walk in the park – you're going to get sick, your balance will be off after this. Nothing is going to be easy," he continued, memories of his own attempt at the trials firmly at the top of his mind.

Cas snorted, amusement tugging at his lips. "Sam, since when has anything we've ever attempted ever been easy?"

And really, there was nothing that Sam could say to that.

Sam stood outside the door of Walsh's penthouse apartment, impressed despite himself; the building was intimidating to say the least, all white walls, glass and gold embellishments, definitely a residency of the wealthy. He wasn't worried about Walsh being at his restaurant – he'd checked there earlier and discovered that the chef had 'come down with a sudden illness', the head waiter had informed Sam. He hadn't been to work all week.

Cas, meanwhile, was standing in the centre of the hallway, eyes trained on the elevator ten metres in front of him. Knowing Hell's sense of humour, the hellhound would almost definitely arrive with a 'ding'. It also helped that he'd lined the hallway with goofer dust, leaving only the elevator entrance clear of the voodoo magic. Earlier, he'd broken into Walsh's apartment and also enclosed it with a line of the dust. Walsh himself was currently inside yet another circle of the stuff, firmly duct-taped to a chair – Sam and Cas were taking no chances of having the victim flee, and lose the chance to take out a hellhound.

It all happened rather suddenly; the clock above the mirror in the centre of the hallway struck twelve, the lift dinged, and the doors slid open with a gentle hiss. With his fading grace, Cas was forced to rely on the hellhound glasses to see the beast, and see it he did, albeit as an indistinct blur consisting of roiling blue mist and few defined shapes. However, it was certainly clear enough to make out where vital arteries would lie beneath hellish skin.

Cas took a step forward, towards the advancing hellhound, which growled low in its throat, a warning in the awful sound – leave now, or pay the price. A sudden and vicious smirk appeared on Cas's face – he'd destroyed thousands of demons fighting to raise Dean from perdition; as if a mere _hellhound_ could stop him. He strode forward confidently, and the hellhound leaped for him, knocking him to the ground and so began the wrestling match of the century. If only there'd been cameras to record the moment, Cas could've become the most famous wrestler the world had ever seen.

While most assumed that a fallen Castiel would be useless, as Dean had once said, a 'baby in a trench coat' that was an incorrect assumption. The fact that Castiel had been a warrior for _millennia_ always seemed to sleep people's minds, as though he hadn't spent his entire life _fighting_. Just because his grace was stolen, and fast diminishing didn't mean that he'd be useless – he still had knowledge of every style of fighting mankind had created, and a few others that they hadn't. And now he was proving it, rolling over and over on the plush red carpet, forcing the hellhound away from his throat as Sam watched on warily, ready to intervene if it looked like Cas was going to die.

And just as suddenly as it began, the fight was over, and Castiel was soaked from head to toe in the blood of a hellhound. He shoved the corpse off and staggered to his feet, spitting out a mouthful of black blood that most certainly wasn't human. Sam was at his side in an instant, supporting the unbalanced angel as he began to chant. "_Kah nuh ahm dahr." _ Light flared beneath his skin, pulsing almost as bright as the sun before fading, leaving Cas doubled over in pain, gripping almost as tightly to Sam's forearm as he had to Dean's shoulder when he'd pulled him from Hell.

A strange revelation hit Cas that he somehow managed to relate almost everything back to Dean, and he wondered if it was normal. But then Sam was speaking in his ear, and by his father, Cas _hurt_. But a triumphant grin lit up his features – he was one step closer to atoning for his sins, but more importantly, he was one step closer to saving Dean.


	3. To Free An Innocent

"Cas," Sam said thoughtfully a week after the first trial had been completed, "who are you going to pull from Hell?"

Cas looked across at Sam from where he was draped across a couch in the library, attention focused on the chandelier above him. "Pardon?" He asked, his voice low and weary. The effect of the first trial had hit him hard, and it was only the second day since he'd managed to stumble out of bed, having been bedridden from pain and exhaustion the days previously.

Sam gave him a sympathetic smile. "Who are you going to rescue from Hell?" He repeated and Cas's face scrunched up as he considered their dilemma.

"That's a good question," he murmured. "But it probably won't be difficult to find someone, not with all the soul-harvesting Abaddon was doing."

"Oh yeah," Sam murmured. "So, you're just going to pop down there, grab the first innocent you see and pop back up?" A note of hope lit up an otherwise monotone voice that had rarely wavered since Dean's turn to darkness.

Cas laughed, but there was little humour in the sound. "That sounds about right," he said dryly. "Of course, that's if I have enough grace left to make the return journey."

Silence filled the bunker once more at Cas's brutally honest statement, both men retreating to their thoughts.

Finally, Sam had to succumb to tiredness. "I'm done for," he muttered at last, snorting bitterly at the double meaning in his words. "Night Cas."

"Goodnight Sam." And then Sam strolled out as though he hadn't a care in the world, but Cas could read the tension in his shoulders, the despair in his hanging head and he didn't say anything. There was nothing he could do to make Sam feel better, not when he didn't even know how to help himself.

Sam paced anxiously around the bunker's kitchen, glancing at the clock every few steps. He now understood how useless Dean had felt when Sam had undertaken the second trial, fretting and worrying but unable to do anything, because he was stuck on Earth, while Cas was in freaking _Hell_. Literally. Again. The fact that Cas had rescued others from Hell previously did little to calm Sam's racing thoughts – What if he failed or screwed up like he had when he pulled Sam from the Cage? What if he didn't have enough mojo to get back? What if he couldn't find a soul to rescue? What if – Sam stopped himself. He couldn't afford to think like that. Not when Dean's life depended on Cas.

If Cas had a chance to save Dean, Sam knew, then not even the combined efforts of Heaven, Hell and Purgatory could stop him.

The world was burning, great chasms of fire and molten rock creating terrifying patterns across the scarred and blackened earth. Smoke and screams choked the air, terrified shrieks of the dead and howls of the tortured mingling with the fumes of burning brimstone.

Hell was different for every soul, Castiel knew, and for him it was like the heart of a volcano, all pressing heat and heavy rock, accented by hideous gases and the cries of the insane, tortured and the gleeful laughs of the torturers. His Hell was not a pretty place. But worst of all was the endless chuckle that vibrated through the air, sometimes so quiet he had to strain to hear it under the screams, and sometimes so loud that he could feel it in his bones. It was a dark, cruel laugh that Castiel had heard only once and it had haunted him ever since – it was the laugh of Dean Winchester as he tortured souls in Hell after unknowingly breaking the first seal.

Cas gritted his teeth. He had work to do.

"Cas, Cas man, are you okay?" Sam asked frantically, dropping to his knees with a thud beside Cas's body. The angel blinked wearily, confusion clouding his eyes before realisation hit him. He sat up with a groan, and Sam gripped his shoulder, steadying him.

"Cas?" Sam asked again, but the angel just shook his head. 'How could anyone be okay after going to _Hell_,_' _was the implied message in that action. Sam winced as he got the unspoken message, guilt flashing across his face.

"Knife," Cas croaked, and Sam instantly thrust Ruby's knife into the other's trembling hand. With a grunt of pain, Cas pressed the blade against his left forearm, drawing blood, and then the knife fell from his fingers as he slumped against Sam. The beautiful, _warm_ glow of a human soul filled the room, and the light entranced the hunter, until he realised that the light was far too brilliant for merely one soul.

He stared in awe at Cas as he realised that the falling angel had pulled not one, not two, but three souls from Hell, had saved three innocents from eternally burning. And then once again, Cas muttered the horribly familiar "_Kah nuh ahm dahr," _and promptly fainted, even as the orange glow of a successful Hell Trial danced beneath his fair skin and he screamed unknowingly, a terrible sound that was terrifyingly similar to those of souls in the pit.


	4. To Save Dean Winchester

They were close, both Sam and Cas could feel it, could sense the familiar feeling of Dean, even though it was warped and twisted, darkened and tainted almost beyond recognition. Yet still Castiel knew it, and he knew that Sam did too when their eyes met. The hunter and nearly-human angel sat together in silence in the Impala outside a bar in the town where it all started; Lawrence, Kansas.

"Why did he come back here?" Sam asked suddenly, his voice cracking. Castiel just stared out the window, only the tensing of his shoulders showing that he'd heard the other.

"How are we going to do this?" Sam asked an hour later and at last Castiel gave Sam an answer.

"You go in the front door and distract him, I'll go in through the back and then hopefully get him into these," Cas said wearily, holding up the demon shackles. Sam eyed the magic cuffs with a mixture of apprehension and guilt.

"Will they be enough to hold him?" He asked, and Cas nodded.

"They held Crowley well enough," he reminded Sam. "And they've only got to last until we can get him into the back."

"He's going to kill us for it, you know that right?"

Cas laughed, a dead laugh that Sam had become horribly familiar with in the months since the other Winchester had become a demon. "He can try." The 'we're already dead' went unspoken but not unheard. For a moment Sam wondered why both he and Cas were refusing to mention his brother by his name, but then his gaze hardened. The thing wearing his brother's meatsuit wasn't his brother, nor really.

And yet, deep down, Sam knew it was.

"Hey Sammy, long time no see." Dean was lazing against the bar inside the crowded room, his clear green eyes taking in the den of human depravity and sin. He lifted a glass of whiskey to his lips as he smirked at his little brother, the amber liquid glinting as it reflected what little light the crowded room had to offer.

"Hi Dean," Sam said tightly, adjusting his grip on his knife. "Been having fun?"

Dean grinned viciously, a sight that had been known to send monsters running. "Actually, I have," he said cockily. "Although I was expecting you long before this. Have trouble finding me, or were you too scared to face me? Inner demons and all that crap?"

"Oh, I found you easily enough," Sam returned sharply. "You're predictable, you know that right?"

"Oh baby, I'm only predictable when I want to be," Dean retorted smoothly, and then for a brief moment his eyes flashed black and Sam reflexively took a step back, glancing warily at the civilians in the room. If anyone had seen, he realised, they'd pass it off as a trick of the light. When Sam looked back at his brother, only to find him standing right in front of him where previously he'd been three meters away, he flinched.

"See?" Dean mocked, "I got you there, didn't I, little brother?"

Sam swallowed, shoving down his fear and grief; his big brother was most definitely taking all too well to being a denizen of Hell. "Whatever you say, Dean." And then Cas was there, and Dean was swearing, because Cas had moved so fast to put the cuffs on that neither of the brothers had noticed until they were on.

"Cas, what the hell?" Dean asked, sounding for a moment almost like his human self as he scowled at the demon cuffs, giving them a few experimental tugs before turning to Sam and Cas with a look of resignation.

"I should be saying that to you," Cas retorted. "You are the demon in this relationship after all."

"Oh, the angel has a bark to match his bite!" Dean crowed, his mood changing with all the speed of the wind and Sam's mouth tightened as he sensed Cas stiffen ever so slightly beside him. Neither took their eyes off of Dean for a second.

Sam glanced at Cas. "Let's go, before he causes a scene."

"Oh, Sammy," Dean said, looking hurt. "I would never."

"What. Did. You. Do?" Dean yelled, causing Sam and Cas to wince in unison even though they'd been expecting such a reaction.

"Uh," Cas said, glancing at Sam, who gave him an encouraging smile, or at least a weak attempt at one. "What was necessary?"

"It was not necessary to draw on my Baby," Dean snapped, and Cas looked warily at Sam.

"It was this or we stuck you in the trunk," Sam came to Cas's rescue, and Dean just glared at the pair of them, his eyes flicking to black. Castiel thought that perhaps they should've just shoved him in the trunk anyway. At least then they wouldn't have to see Dean every time they looked into the back of the Impala, trapped inside a demon trap drawn on the roof of the Impala.

"I'm going to kill you," Dean promised, none of his earlier humour remaining, his face serious.

"We know," Sam murmured. "We know."

"What are you doing?" Dean asked as Sam parked the Impala outside of an abandoned church. Sam glanced over at Cas who merely shook his head. Neither answered the demon in the backseat who'd been bitching the entire drive.

"Sammy," Dean said. "Don't tell me this is what I think it is."

Sam looked back at Dean. "It's not what you think it is," he informed his brother whose eyes turned black once again.

"You don't get to kill yourself to save me; we've been through this before," Dean warned as Castiel dragged him into the church and sat him down on the demon chair he and Sam had placed there earlier.

"Don't worry about Sam," Castiel sighed as he tightened the chair's collar around Dean's neck.

Dean snorted. "Demon or not, of course I'm going to worry about my little brother," he retorted, wiggling around to get more comfortable. The solid metal chair, however, was unrelentingly uncomfortable in whatever position he sat, and he finally settled as Cas knelt to lock the latches around his ankles.

"Always imagined you on your knees in front of me, Cas," Dean grinned, "but I have to admit, this is definitely not the context I wish it was."

Cas stoically ignored Dean's not-so-subtle innuendo, ignoring what the 'always' implied. He got to his feet and closed the latches around Dean's wrists, removing the cuffs with a frown.

Dean smirked up at him. "You like how the cuffs look on me, huh? Maybe we can have some fun? Wouldn't that be a scandal, a demon going down on an angel, or maybe an angel going down on a demon. You'd like that, wouldn't you?"

Cas finally met Dean's eyes. "I'm not an angel anymore," he informed the demon, whose eyes widened at the revelation. "I used up the last of my grace getting you into these cuffs before it could burn out."

"Oh," Dean said softly, and for a moment Cas had hope that somehow the three of them could fix this, that he wouldn't have to- "Well, a human banging a demon is still pretty kinky," Dean winked, and Cas growled under his breath, stalking away from the crass demon to clear his head.

"You okay?" Sam asked Cas cautiously as they stood together at the far end of the church watching Dean. He clearly hadn't heard what his older brother had been saying to the newly-fallen angel.

Cas closed his eyes, shaking his head with a pained expression. "I'm not going to be okay until this is over, Sam," he murmured and Sam watched him carefully. It was rare for Castiel to show such emotion, even now that he was human.

"You do know what this is going to cost?" Sam asked cautiously, suddenly fearing that the other didn't know, was going into the third trial blind.

"Of course I do, and I've said it before, I'm always happy to bleed for the Winchesters." Cas retorted sharply, meeting Sam's concerned eyes with angry blue ones.

"This is more than a little blood, Cas," Sam said, not rising to the fight that Cas was apparently so desperately seeking. It hurt to see the similarities between his brother and Castiel, knowing that Dean had been the ex-angel's role model for years now. "I'm going to miss you – Dean's going to miss you, even if he does curse you until he's blue in the face."

"Then it's a good thing I'm not going to be around to hear it, isn't it?" Cas asked, his head dropping in defeat and Sam gripped his shoulder.

"Cas…"

"Don't, Sam. I have to do this. I - I owe it to Dean."

Sam shook his head. "You don't owe Dean anything."

Cas snorted. "Love is a debt Sam, and it's one that I'm not leaving unpaid." And then he turned, slipping into the confessional, leaving a wide-eyed Sam outside to reinterpret his memories of the past five years.

"Cas," Dean sobbed, thrashing wildly against his restraints. "Cas, don't do this, you're going to die!"

"Dean, I know," Cas said calmly as he readied the last syringe of his purified blood. The third trial was nearly over, and he was barely standing. Sam was outside, keeping watch for Crowley's minions – there was no way the King wouldn't be searching for his new favourite pet. "And it's okay."

Dean shook his head wildly. "No, Cas, it's not, I need you, don't make me human without you," he pleaded, but Cas just gave him a small smile, a gesture that was so _Cas_ but still so unfamiliar that it hurt the almost-human demon.

"It's okay," Cas whispered, and he pressed his forehead against Dean's, effectively stopping the nearly-human demon's trembling. "It's okay. You'll have your brother, and that's all you two need; each other. Besides, I'm human now – we'll see each other again in Heaven if your friend Ash has anything to say about it."

"Cas…"

And then Cas plunged the syringe full of his blood into Dean's arm, forcing the thick liquid into the other's body. Dean looked up at Cas, practically begging now. "Don't do it."

"I have to," Cas replied determinedly as he pulled the needle from Dean's arm. "_Exorcizamus te, omnis immundus spiritus... Hanc animam redintegra… Lustra! Lustra!"_

"Cas," Dean whispered. "Don't, I need you."  
"I know Dean, I need you too," Cas murmured and then he placed his bloody palm over Dean's mouth, gritting his teeth against Dean's inhuman scream as he became human once more and was shoved forcefully back into his body. For a brief moment, Dean's eyes met Cas's, and then Cas spoke again.

"_Kah nuh ahm dahr."_

And then it was over, and in an abandoned church in Kansas there were two broken brothers and the body of a broken angel, and there they stayed even as a great wall of fire purged the surface of the earth, burning every demon from the world and casting them back down to Hell.


	5. Epilogue

"So," Dean said on a rainy day a few weeks later, walking into the bunker kitchen. His voice was hoarse and sore from disuse. Sam looked up at his brother with wide eyes from where he was eating his breakfast. Dean hadn't spoken to him since Cas had…

"Dean?"

"You uh, you just let him sacrifice himself?" Dean asked, settling into a chair with a thud, and Sam looked away, guilt burning him from the inside.

"Yes."

Silence. Then, "Why?"

"Because you'd have done the same for me," Sam said tightly, refusing the urge to look at his brother.

"Did it ever occur to you that you could just, you know, cure me and _not _do the Hell Trials? Not sacrifice our only friend?"

All the air left Sam's body. Oh god, he realised. Why hadn't Cas suggested that? "No," he said, and he finally chanced a look at Dean, whose face was set in a frown. He looked tired, Sam noted, tired not just physically, but tired in his soul.

"He always was a determined son of a bitch," Dean said quietly. "God knows, it's one of the things I – I loved about him." Sam remained silent despite the fact that he was tearing himself apart on the inside. Why hadn't he noticed that Cas was _trying_ to kill himself, even if he was going about it subtly? Sam _knew_ what the trials would ask for, and yet he still let the angel do it.

Dean wasn't finished, and Sam listened, knowing that his brother had to say it and be heard. "He deserved better. He didn't deserve to fall for me," Dean laughed bitterly. "Pun intended." The hunter shook his head, shifting his dead gaze to meet his brother's eyes. "I need him," he whispered and Sam swallowed down bile that was being forced up by his guilt.

"I'm sorry," he whispered and Dean grimaced.

"I know. And I wish that it could fix," Dean waved a hand between his brother and himself, "this. But it can't. We're royally fucked up, Sam. This can't… it can't keep on going like this, one of us dying for the other and then the other doing something ridiculously stupid to get the dead one back. It's not natural."

Sam knew where this was going. "Dean… don't," he pleaded.

"I'm not Sammy, don't worry about that. But… it really does need to stop. And next time you die, I swear I won't bring you back. Now promise me the same Sam," Dean's voice was soft, tired, _done._

"Dean, I can't – I can't, you can't make me," Sam said, his eyes fixed on his brother's head which was now turned away from him.

"Promise or I'm out," Dean said unrelentingly. "And you won't be able to find me."

And Sam was left with a choice. Lose his brother permanently now, or lose him permanently later. He swallowed. "I promise," he muttered at last and Dean looked back at him, relief in his eyes.

"That's uh, that's good." Dean got to his feet and stood uncertainly for a moment before ruffling Sam's hair and wandering out into the rest of the bunker, leaving his brother alone with his cereal once again.

Sam stared at the soggy food blankly, but the guilt in his stomach had removed any trace of hunger he'd felt previously. Somehow, Sam knew, he was going to have to face his guilt, but for now he was going to ignore it, because he couldn't deal with it, not right now.

He couldn't deal with the guilt because Sam had let Cas kill himself and had thus broken his brother more completely than even Alastair had, but most of all he couldn't handle the guilt that came with being a liar.


End file.
